Mr Clegg described his decision on tuition fees as ‘brave’ and worth the short term political damage.

He said that if Mr Miliband or Mr Cameron believe they can win a majority then they need to lie down in a dark room.

All leaders were asked about post-election deals.

Ed Miliband remained firm in his refusal to form a coalition with the SNP.

David Cameron said the Conservatives are aiming for an outright majority.

Nick Clegg hopes a coalition with the Liberal Democrats will keep the next government from lurching left or right.

An instant poll of Question Time viewers by ICM for The Guardian showed that 44% thought Mr Cameron had ‘done best on the night’, against 38% for Mr Miliband and 19% for Mr Clegg.

Only 6% of viewers in a small sub-sample said they had their mind changed by the programme.

87% said it would make no difference to how they would vote.

When they left the studio set LMMN took screenshots of how the party leaders looked.

Mr Cameron smiled and looked pleased with himself; the Labour leader Ed Miliband stumbled and nearly fell over, but managed a cheery wave, and Nick Clegg looked rather relieved it was all over stepping off the podium gingerly.

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All three leaders were asked about immigration. Nigel Farage of UKIP also addressed the issue on the BBC programme Ask Nigel Farage.